108 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



quantity of it is unfortunately limited, and recourse has to be had to ponds, 

 streams, springs, or public water supplies, often of very varying character. 



A hard water is, generally speaking, one rendered so by the presence 

 of salts of lime and magnesia, and is of two kinds : '* temporary " hardness, 

 where the lime is present as carbonate of lime, and which water can be 

 rendered soft by boiling ; and M permanent " hardness, where the lime 

 and magnesia are present largely as sulphates, and which cannot be 

 deprived of its hardness by bailing. 



Hard waters, of whichever type, are known to be very bad for such 

 plants as do not thrive on a soil rich in lime ; among these are the heaths 

 azaleas, rhododendrons, Arc, and hard water should on no account be 

 used for them. Hard water is also bad for foliage plants and ferns. 



Other waters may contain a large quantity of dissolved salts, such as 

 common salt, sulphates of soda and magnesia, nitrates and the like. 

 Some of these may, indeed, be quite saline or brackish, and may, as a 

 class, be set aside as undesirable, though, if the salinity be due to nitrates, 

 it may be beneficial rather than otherwise, and equivalent to a manuring 

 with nitrate of soda or potash. When a water is of " temporary hard- 

 ness " character, this is due mostly to its being derived from chalk or 

 limestone, and it is possible by treating this in one tank with milk of lime, 

 and allowing the clear water, after settling out of the lime, to pass int3 

 another tank, to have for horticultural use a regular supply of softened 

 water. To obtain a satisfactory result, however, it is necessary to adju:t 

 the quantity of added lime to the proportion of lime in the original water, 

 and for this purpose the aid of the chemist should be sought. With 

 other waters containing excessive dissolved matters nothing practicable 

 can be done, and the best thing, if a better supply be not available, is to 

 dilute them as far as pcssible with rainwater. In a case recently referred 

 to me, the gardener of one of our largest landowners sent me up samples 

 of the waters used in the gardens, and complained that one of them which 

 was being used chiefly for plants had a serious effect upon them. On 

 analysis I found the waters to give the following results : — 



e n. 



Grains per gallon. Grains per gallon. 

 Total solid residue . . . 181-52 17 53 



Chlorine 74*90 120 



Equal to chloride of sodium . 125*34 1*95 



No. I was the water complained of; the residue consisted mainly of 

 chloride of sodium (common salt) and chloride of magnesium, together 

 with a certain amount of lime salts, and the water had a distinctly saline 

 taste. A water with so much saline matter in it is one quite un suited for 

 horticultural use, and I have no doubt that the injury to the plants was 

 caused by its use. No. H. on the other hand, was a water that cculd quite 

 well be used. It may be of interest in this connection to say that the 

 Royal Horticultural Society, on acquiring their new grounds at Wisley, 

 had the water supplies there analysed, and with satisfactory results, the 

 water from the Upper Well showing only 11-48 grains per gallon of total 

 solid residue, and that from the Lower Well 28*56 grains per gallon, the 

 former thus being the more generally suitable for garden uses. 



